View Single Post
  #54  
Old 05-26-2007, 06:50 PM
b3lha's Avatar
b3lha b3lha is offline
Phil & Belha
 
Join Date: Aug 2001
Location: Alcyone Limited, Buckinghamshire UK
Posts: 2,671
Quote:
Originally Posted by Nomake Wan
Phil!!! I found something really interesting while perusing the TSB page linked in the General forum... it's a whole TSB about communicating with the Cruise Control Computer through the select monitor!!! Uploaded it to my locker for ease of access.

http://www.subaru-svx.net/photos/fil..._Wan/44146.pdf

Hopefully it will help somehow.
Good find Nomake! Thanks!

It corroborates what I found in the service manual. Actually, your post inspired me to do a little more investigation on the cruise control unit and I found something rather puzzling. The TSB you found says that the cruise control master switch must be turned on.

The unit that responds to command "89", sends responses even when the cruise control master switch is off. And the data doesn't change when I wiggle the cruise engage lever. So it probably isn't the cruise control unit sending the responses.

Heaven knows how you get the cruise control unit to respond, I've tried every command from "00" to "FF" and the only ones that respond are 78(ecu), 45(tcu) and 89. There is an extra wire in the select monitor plug that goes to the cruise control unit, so I reckon that you have to do something with that wire to get data from the cruise control.

The other question is, what unit is responding to command "89". I thought that the only units connected were the ECU, TCU and Cruise. So I had another look at through the (USDM) wiring diagram and found that the Aircon unit is also connected. So I turned the Aircon panel off, but the unit still responds, so it's not the Aircon either - Unless the Aircon controller is still powered when the control panel is turned off.

I can't think what else it could be. The other thing I noticed is that the mysterious unit 89, stops responding when the engine is running. It only talks to the select monitor when the engine is off, but the ignition is on.

It's a mystery to me.
__________________
Subaru ECU and TCU Website
1992 Alcyone SVX Version L
1992 Alcyone SVX Version L
1994 Alcyone SVX S40-II
2004 Subaru Legacy 2.5 SE Sports Tourer
1996 Subaru Legacy 2.2 GX Wagon
1988 Subaru Justy J12 SL-II

Last edited by b3lha; 05-26-2007 at 06:53 PM.
Reply With Quote